Our return date will be depending on the cost of airline ticket.
- Probably not what you want. Maybe use this if you know that your return date will depend on the cost in the future, but you haven't chosen a tentative return date yet.
Our return date will depend on the cost of airline ticket.
- This is probably what you want. This implies the return date is in the future, and not yet certain.
Can somebody explain the difference between these two, I don't see any differences both are in the future and will depend on the cost of airline tickets may be will be depending is less sure